A new version of the RegCM regional climate modeling system, RegCM4, has been recently developed and made available for public use. Compared to previous versions, RegCM4 includes new land surface, ...planetary boundary layer, and air–sea flux schemes, a mixed convection and tropical band configuration, modifications to the pre-existing radiative transfer and boundary layer schemes, and a full upgrade of the model code towards improved flexibility, portability, and user friendliness. The model can be interactively coupled to a 1D lake model, a simplified aerosol scheme (including organic carbon, black carbon, SO₄, dust, and sea spray), and a gas phase chemistry module (CBM-Z). After a general description of the model, a series of test experiments are presented over 4 domains prescribed under the CORDEX framework (Africa, South America, East Asia, and Europe) to provide illustrative examples of the model behavior and sensitivities under different climatic regimes. These experiments indicate that, overall, RegCM4 shows an improved performance in several respects compared to previous versions, although further testing by the user community is needed to fully explore its sensitivities and range of applications.
The PiSQRD web resource can be used to subdivide protein structures in quasi-rigid dynamical domains. The latter are groups of amino acids behaving as approximately rigid units in the course of ...protein equilibrium fluctuations. The PiSQRD server takes as input a biomolecular structure and the desired fraction of protein internal fluctuations that must be accounted for by the relative rigid-body motion of the dynamical domains. Next, the lowest energy modes of fluctuation of the protein (optionally provided by the user) are calculated and used to identify the rigid subunits. The resulting optimal subdivision is returned through a web page containing both interactive graphics and detailed data output. Availability: The PiSQRD web server, which requires Java, is available free of charge for academic users at http://pisqrd.escience-lab.org. Contact: potestio@sissa.it
The ALADYN web server aligns pairs of protein structures by comparing their internal dynamics and detecting regions that sustain similar large-scale movements. The latter often accompany functional ...conformational changes in proteins and enzymes. The ALADYN dynamics-based alignment can therefore highlight functionally-oriented correspondences that could be more elusive to sequence- or structure-based comparisons. The ALADYN server takes the structure files of the two proteins as input. The optimal relative positioning of the molecules is found by maximizing the similarity of the pattern of structural fluctuations which are calculated via an elastic network model. The resulting alignment is presented via an interactive graphical Java applet and is accompanied by a number of quantitative indicators and downloadable data files. The ALADYN web server is freely accessible at the http://aladyn.escience-lab.org address.
Over the last few years, an increasing number of companies have introduced or plan to adopt some kinds of e-Business solutions. They allow new forms of communication between buyers and sellers and ...they are expected to provide opportunities to create new marketplaces, whilst firm's productivity and efficiency should benefit. Because of the recent history of such type of projects, it hasn't been possible yet to identify neither clear guidelines for the implementation process nor evaluation procedures for assessing the validity of a certain e-Business project. Furthermore, it has to be noted that a high number of e-Projects have failed or haven't led to the expected results. This paper focuses on a particular aspect of this new way of doing business: the transfer of a part of purchasing activities on the net, the so called e-Procurement. The proposed methodology aims to give a structured procedure for both a quantitative and a qualitative evaluation of a certain e-Procurement investment starting from the identification of the main relationships among relevant elements influenced by the e-Procurement introduction (activities, performance indicators and company's features). The analysis also includes some considerations of a strategic nature and should lead to the reduction of a final report which has to support managers during the investment decision by highlighting expected benefits. The application of the proposed methodology to an Italian firm which has introduced the e-Procurement is described.
Sm2Fe17N3 powders were prepared by a novel molten-salt mechanochemically assisted reduction-diffusion (RD) approach. CaCl2, plays a critical role during mechanochemical processing as a dispersant, ...facilitating the RD process by dissolving the precursors in a molten flux and further assisting during the washing step by efficient removal of by-products thus minimizing the surface oxidation of Sm2Fe17N3 powder particles. Various milling times and RD temperatures were examined, and synthesis conditions were optimized to achieve pure-phase Sm2Fe17N3 powders with low aggregation of magnetic particles. Powders synthesized at 950 °C RD exhibited the highest hard-magnetic properties: coercivity Hc of 13.5 kOe, and maximum energy product (BH)max of 19.4 MGOe. This was attributed to the formation of fine single-phase Sm2Fe17N3 particles as well as minimal oxidation of particle surface. Furthermore, by densifying the Sm2Fe17N3 powders with high-pressure spark plasma sintering, a bulk magnet with (BH)max of 16.5 MGOe and a relative density of 86 % was produced indicating that the obtained Sm2Fe17N3 powders had low oxygen content.
•Sm2Fe17N3 magnetic powders were synthesized by novel molten-salt RD process.•BM mechanochemically activates the precursors and promotes homogeneous mixing.•CaCl2 aids in RD by dissolving precursors and facilitates washing.•Optimizing the developed procedure yielded Sm2Fe17N3 powders with (BH)max = 19.4 MGOe.•Sintering powders produced magnet with (BH)max = 16.5 MGOe and 86 % relative density.
ExaNest is one of three European projects that support a ground-breaking computing architecture for exascale-class systems built upon power-efficient 64-bit ARM processors. This group of projects ...share an "everything-close" and "share-anything" paradigm, which trims down the power consumption - by shortening the distance of signals for most data transfers - as well as the cost and footprint area of the installation - by reducing the number of devices needed to meet performance targets. In ExaNeSt, we will design and implement: (i) a physical rack prototype and its liquid-cooling subsystem providing ultra-dense compute packaging, (ii) a storage architecture with distributed (in-node) non-volatile memory (NVM) devices, (iii) a unified, low-latency interconnect, designed to efficiently uphold desired Quality-of-Service guarantees for a mix of storage with inter-processor flows, and (iv) efficient rack-level memory sharing, where each page is cacheable at only a single node. Our target is to test alternative storage and interconnect options on actual hardware, using real-world HPC applications. The ExaNeSt consortium brings together technology, skills, and knowledge across the entire value chain, from computing IP, packaging, and system deployment, all the way up to operating systems, storage, HPC, big data frameworks, and cutting-edge applications.
We present a computer simulation study of the dynamical properties of a nematic liquid crystal model. The diffusional motion of the nematic director is taken into account in our calculations in order ...to give a proper estimate of the transport coefficients. Differently from other groups we do not attempt to stabilize the director through rigid constraints or applied external fields. We instead define an intrinsic frame which moves along with the director at each step of the simulation. The transport coefficients computed in the intrinsic frame are then compared against the ones calculated in the fixed laboratory frame, to show the inadequacy of the latter for systems with less than 500 molecules. Using this general scheme on the Gay-Berne liquid crystal model, we evidence the natural motion of the director and attempt to quantify its intrinsic time scale and size dependence. Through extended simulations of systems of different size we calculate the diffusion and viscosity coefficients of this model and compare our results with values previously obtained with fixed director.
The Abdus Salam International Centre for Theoretical Physics (ICTP) is concluding a three-year project Special African Project with a component aimed at building Computational Research ...Infrastructures for Africa. The component, with funding from the Italian government, will setup a few Computational Physics/ High Performance Computing (HPC) Centres in sub-Saharan Africa. This component will foster the implementation of low cost commodity based Linux clusters of 5-32 nodes with an emphasis on building sustainable/self reliant capacity for implementing and maintaining Linux based commodity clusters, providing end-user support for HPC applications, porting applications to HPC environment and researching new HPC technologies. ICTP has a longstanding tradition in building scientific capacity in the developing world and champions the use of HPC and ICT tools in a supporting role to scientific development: even in the young area of HPC several capacity building activities have been organized in partnership with the DEMOCRITOS National Simulation Center/SISSA Joint Laboratory for e-Science. In this paper we will focus on the successful approach to capacity building used for the above subproject that has lead to the creation of an active team of HPC training instructors and computational scientists in the sub-Saharan region who are already making an impact on scientific development on the continent. We describe our methodology, the approach employed during the different training events and the lessons learnt from our training experiences that improved the capacity building aspect of the sub-project.
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